The first living creature in space was a small mixed-breed dog named Laika ('Barker'), who was launched aboard Soviet Sputnik 2 on November 3, 1957. Laika was also the first living creature to die in space - she survived, frightened and alone, for a week before dying of unknown causes.
Animals have paved the way for humans to experience space flight. A group of twenty-five Wistar rats was included on the Cosmos 782 mission in 1975. They were the first rats in space, and a quick check on the NASA 'Life Into Space' site reveals hundreds more.
Although the thirteen lost rats were small in size, they made the largest sacrifice possible. And remember, animal astronauts are never given a choice.